Avalanche Forecast
Issued: Dec 5th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
bchristie,
Avalanche Canada
Avoid fatter, wind loaded pockets of snow on slopes over 25 degrees. Wind slabs sitting on top of a crust are the biggest concern right now.
If your area received moderate wind and more than 10 cm of snow in the last 48 hours, increase treeline hazard to Moderate.
Summary
Confidence
Weather Forecast
Sunday Night: Partly cloudy. Possible trace of new snow. Moderate to strong west wind. Alpine temperature around -17.
Monday: Partly cloudy. No new snow expected. Moderate west to northwest winds. Alpine high above -15, with a possible temperature inversion starting to set up.
Tuesday: Overcast. 3-7 cm of snow expected, heavy snow starting overnight and into Wednesday. Strong to Extreme southwest winds. Alpine temperatures above -10, with a possible temperature inversion.
Wednesday: Mostly cloudy. 10-30 cm snow expected. Strong west to northwest winds. Alpine temperatures around -10.
Avalanche Summary
No new avalanches observed.
This Mountain Information Network (MIN) post paints a great picture of conditions in the Cowmoose area on Saturday!
Our North Rockies field team has started their season. They regularly post on the MIN, but you can also give them a follow on Instagram to get lots of great conditions reports and avalanche info:)
Recently, a few large avalanches were observed in the Southeast corner of the region. These avalanches ran on a deep persistent layer, likely one of the crusts from late October or early November.
Snowpack Summary
Saturday night, snowfall was variable across the region. Some areas received up to 15 cm of snow.
Elsewhere, clear, cold nights have promoted surface hoar growth. 5-10 mm surface hoar has been observed in the far south of the region, and is expected to be found in other areas. If you are out in the backcountry, keep an eye out for where it has formed. It may become a new sliding surface as the next storm rolls in on Tuesday night.
Wind slabs will be found in wind exposed terrain in the treeline and alpine. A crust exists below 1700 m.
The mid snowpack may contain a number of crusts from early to mid November. There is the potential for faceting near these crusts, making them potential sliding layers with the right load or trigger.
The lower snowpack consists of a series of early season crusts. These appear to be strong, but shallow alpine slopes along the eastern side of the Rockies towards Jasper may have weaker, faceted snow near the ground. Avoid thick to thin areas where you are more likely to be able to trigger this deeper instability.
Snowpack depths are anticipated to be approaching 3 m in the alpine and around 150 cm at treeline.
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Wind slabs may be poorly bonded to the underlying crust.
Problems
Wind Slabs
Yesterday's forecaster blog does a great job of capturing the challenging travel and decision making we'll likely encounter in the backcountry right now.
Wind slabs are likely to be found near ridgelines and exposed terrain in the treeline and alpine.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 6th, 2021 4:00PM
